A known internal combustion engine has a casing which comprises interconnected elements and which is connected to the engine housing with interposed vibration-damping means and has a cooling air blower driven by the engine crankshaft, which blower draws in cooling air through an inlet opening in the casing and conveys it through the interior space between the engine housing and the casing, the exhaust air exiting through an outlet opening provided in the casing. An object of the invention is to design the casing in such a way that it ensures an optimum flow of cooling air along the outer surfaces of the engine, enables economic manufacture and assembly, and allows necessary maintenance work on the engine to be performed with minimum expense.
It is an object of the invention to provide access through the casing to the transmission means, coupled to the engine crankshaft, for various external units in such a way that the sound-damping effect of the casing is scarcely impaired thereby.